After a period of adaptation, the body can undergo a series of adaptive changes, such as increasing ventilation, so that the oxygen utilization rate of tissues reaches or approaches the normal level; Accelerate the heart rate and increase the pumping capacity of the heart, thereby increasing the amount of bleeding per minute and improving the hypoxia; Increase the amount of red blood cells and hemoglobin to increase the oxygen carrying capacity, so as to ensure the body's oxygen supply. However, some people are sensitive to the partial pressure of hypoxia in the air and have poor adaptability, and a series of symptoms and changes in functional metabolism will occur, which is also called acute altitude sickness. It is divided into acute altitude sickness, high altitude pulmonary edema, high altitude cerebral edema, high altitude retinal hemorrhage and chronic altitude sickness abroad, and it is divided into acute altitude sickness and chronic altitude sickness at home. For individuals, the onset is often mixed and difficult to distinguish, and it is more prominent at a certain stage in the whole onset process.
Symptoms and self-judgment of altitude sickness
Some people who enter the plateau for the first time will have symptoms such as headache, dizziness, dizziness, tinnitus, general fatigue, difficulty walking and difficulty falling asleep within 24 hours at an altitude of 3000 meters. In severe cases, symptoms such as abdominal distension, loss of appetite, nausea, vomiting, palpitation, shortness of breath, chest tightness, purple complexion, swelling of lips or face appear. When these symptoms appear, you should stay at the original height and rest for 3~5 days, or immediately lower the height by hundreds of meters, which can generally return to normal.
It is reported that the incidence below 3500m accounts for 37%~5 1%, and the incidence between 3600m and 5000m reaches 50%. This shows that the higher the altitude, the higher the incidence of altitude sickness.
Severe altitude sickness is very harmful to human body. Therefore, after entering the plateau, altitude sickness should be considered if the following symptoms appear:
1. Severe headache, palpitation, shortness of breath, chest tightness, loss of appetite, nausea, vomiting, cyanosis of lips and nails.
2. Consciousness trance, cognitive ability plummeted. Mainly in the calculation difficulty. Do a simple addition problem before entering the platform period and record the time spent. When symptoms appear, repeat the same calculation problem. If it takes longer than before, it means that altitude sickness has occurred.
3. hallucinating, feeling warm, and often walking behind others aimlessly.
Preventive measures and drugs to relieve symptoms
Strict physical examination before entering the plateau, severe anemia, hypertension, obvious heart, liver, lung, kidney and other diseases, should not enter the plateau. Due to high oxygen consumption, obese people are generally more likely to suffer from mountain sickness than thin people.
When you first enter the plateau, you should reduce physical activity to protect your heart, so you should strictly control the climbing speed. Generally, it is not advisable to climb more than 1000 meters in one day.
Two days before entering the plateau and three days after entering the plateau, preventive oral administration of some drugs can alleviate the symptoms of altitude sickness:
Acetazolamide 0.25g, twice a day. Acetazolamide itself has diuretic effect, which is mainly used for cardiogenic edema, brain edema and digestive tract ulcer. Preventive use can alleviate the symptoms of altitude sickness. The side effects of acetazolamide are renal colic, kidney calculi, sulfanilamide crystals, nephrotic syndrome and agranulocytosis (sulfanilamide allergy). Long-term use will cause low potassium ions in the blood, so it is necessary to supplement potassium (you can eat oranges or bananas). People with hepatic coma and renal insufficiency should not take it.
Rhodiola is a drug that many people hope to prevent altitude sickness. It has the functions of clearing away heat and toxic materials and removing dampness, and can be used to treat lung heat, pulse heat, plague and limb swelling. In recent years, salidroside has been isolated from Rhodiola in China, which has been proved by experiments to have the effects of strengthening the heart, calming, raising blood pressure and resisting fatigue. Rhodiola extract can be used to resist fatigue, increase physical strength and endurance, and be weak after illness. Whether altitude sickness can be prevented or not has not been found by the author.
According to hypoxia, dexamethasone 0.75~6 mg can be added, 2~4 times a day. The main function of this medicine in relieving altitude sickness hypoxia is to increase the content of red blood cells and hemoglobin, thus improving the oxygen carrying capacity. Dexamethasone is a glucocorticoid drug, and the indications must be strictly controlled. Abuse of this drug will reduce its due effect when it is really necessary to be rescued. Large doses can lead to obesity, elevated intraocular pressure, hypertension, digestive tract ulcers, bleeding and even perforation. Especially for virus-infected people, taking glucocorticoids can spread and aggravate virus infection.
Uloprofen can relieve headache caused by altitude, 50 mg orally, 3~4 times a day. Nifedipine (Xintongding) dilates arterioles, which can reduce pulmonary edema. Moderate sedatives, multivitamins and aminophylline can relieve symptoms.
When entering the plateau, we should also pay attention to a reasonable diet, eat more carbohydrates and eat less indigestible food. Special reminder not to drink. Drinking alcohol will make the heart beat faster and increase the load on the unaccustomed heart; Drinking alcohol can dilate the blood vessels of the whole body, increase the heat dissipation of the skin, and then accelerate the heartbeat again, which greatly increases the chances of vicious circle, heart failure and high altitude brain edema.
Plateau environment and long-term hypoxia can obviously increase the number of red blood cells and blood viscosity. Excessive sweating when climbing mountains, coupled with rapid and deep breathing, increases water consumption in the body and aggravates blood viscosity. Viscous blood leads to poor blood circulation and insufficient blood supply and oxygen supply, so many people have severe headaches, chest tightness, shortness of breath, fatigue and other symptoms, and even lead to heart failure in severe cases. Therefore, drink at least 3~4 liters of water every day to ensure that your body gets enough water. After blood dilution, it can reduce the heart load and relieve the symptoms of altitude sickness. Whether the hydration is reasonable depends on whether the urine volume is sufficient, whether the urine is clear, and pay attention to the electrolyte balance.
High altitude pulmonary edema and brain edema
Altitude sickness seriously threatens people's lives and health. How can we find out in time and help each other on the spot?
High altitude pulmonary edema is a common severe altitude sickness with an incidence of about 3%. It usually occurs above 4000 meters, and it often happens quickly 3-48 hours after climbing, and then in 3- 10 days. The important inducement is respiratory infection caused by cold, fatigue and decreased resistance. When you have a headache, chest tightness, varying degrees of cough (dry cough at first, then phlegm), and difficulty breathing, you can't lie on your back. In severe cases, you will cough up pink foam-like sputum. The rescuer will put his ear close to the patient's chest wall and hear the gurgling breathing sound in the lungs (medically called wet rales). At this time, the patient is frightened, flustered, cyanosis in mouth, lips and face, and in severe cases, hematuria or gradual unconsciousness. Severe pulmonary edema will worsen rapidly, and the patient will be in a coma and die within a few hours.
The first-aid measures for on-site pulmonary edema are to rest in an absolute semi-recumbent position, with legs drooping, and immediately take oxygen, preferably oxygen containing 50%~70% alcohol at a flow rate of 6 ~ 8 liters/minute; Take furosemide (furosemide) 40mg/day immediately. The use of furosemide may cause slight nausea, diarrhea, drug eruption, blurred vision, upright vertigo, muscle spasm, thirst and so on. Be careful not to use too much at first, and you can increase it to 80 mg twice a day according to the situation. Nifedipine reduces pulmonary edema. Antibiotics and dexamethasone 4 mg can be used to prevent and treat upper respiratory tract infection (only once orally). You can use a small amount of sedatives when you are upset. Keep warm and don't drink a lot of water. After initial first aid, the condition was stable and quickly moved to a lower altitude. In case of respiratory or cardiac arrest, perform cardiopulmonary resuscitation immediately.
It should be noted that colds should be avoided as much as possible in plateau areas. When you catch a cold at high altitude, you will have the illusion of fever temperature. The temperature of body temperature is often lower than the actual temperature 1 degree, which is easily overlooked. Even a slight respiratory infection can increase the risk of high altitude pulmonary edema. So keep warm. After entering the plateau, reduce the number of baths or not take a bath. When you find the first symptoms of a cold, take anti-cold medicine immediately. If you take anti-cold medicine after two days, it is generally ineffective.
Patients with recurrent high altitude pulmonary edema are susceptible, and the incidence rate of men is five times that of women. If pulmonary edema has occurred before, we recommend not to climb mountains above 3000 meters.
High altitude brain edema is another serious high altitude disease, which has an acute onset and often occurs at night. The incidence rate is low, but the mortality rate is high. Its symptoms: in addition to early altitude sickness, there are severe headaches, vomiting and even jet vomiting; Gradually trance, poor sense of orientation, personal convulsions, incontinence, and finally lethargy to coma. A few people may have retinal hemorrhage.
In the past, mountain friends always judged whether there was brain edema by experience. The usual method is to let people suspected of brain edema walk in a straight line to judge whether their directional ability is poor. From a scientific point of view, this method is not desirable! The brain tissue of patients with cerebral edema has been seriously deprived of oxygen. At this point, people in a trance state are likely to fall to the ground immediately and fall into a coma. This inspection method that aggravates the damage is risky. The correct judgment method is to let the patient lie in a semi-supine position and guide him to point to the nose, ears, eyes and so on. According to the instructions, see if his movements can be accurate. Once there is no, it means that brain edema may have occurred.
If brain edema and coma are found, oxygen containing 5% carbon dioxide should be given quickly and continuously until waking up, and oxygen should be given intermittently after waking up. Conditional use of hypertonic glucose, mannitol, adrenocortical hormone, cytochrome C and other treatments can reduce brain edema and promote recovery. Central nervous system stimulants such as lobeline hydrochloride and nikethamide can be used as appropriate. Pay attention to the balance of water, salt and electrolyte and the necessary anti-infection measures. After the condition is stable, immediately go down the mountain and rush to the hospital.
In the anoxic environment, people will improve the anoxic state by accelerating and deepening breathing, which will increase the exhaled carbon dioxide and lead to respiratory alkalosis. Respiratory alkalosis not only constricts cerebral vessels, but also leads to loss of consciousness and brain edema at high altitude. The most effective way to prevent respiratory alkalosis is to roll the newspaper into a cone, tear a small hole with a diameter of 1-2 cm at the tip of the cone, and stick the cone-shaped newspaper close to the face, so that the exhaled gas can be sucked back, that is, the exhaled carbon dioxide can be sucked back again, thus improving the pH in the body and correcting respiratory alkalosis.
There is no need to be reluctant to face the plateau.
Not everyone who climbs the plateau will have altitude sickness. The incidence and recovery speed of altitude sickness are related to the individual's compensatory adaptability, which varies greatly among individuals. People who have no altitude sickness this time may not be unresponsive when they climb the plateau next time. Some people have altitude sickness every time. These people are sensitive or highly prone to altitude sickness. What needs to be reminded here is that altitude sickness cannot be overcome by repeated exercise. Therefore, in order to ensure good health, it is suggested that people who are prone to altitude sickness should not continue to climb such high-altitude areas. Fitness mountaineering in low-altitude areas can also cultivate sentiment and exercise.